module.exports = {

    UploadObject: class UploadObject {
        constructor(db) {
            this.db = db;
            this.absrc = ['E', 'T', 'X', 'W', 'U', 'R', 'J', 'I', 'N', 'C'];
            this.loaded = false;
            this.num_files = 0;
            this.fileCache = {};
        }

        new(num_files) {
            if (!this.loaded) {
                if (typeof num_files == "number" && num_files > 0) {
                    this.num_files = num_files;
                } else {
                    console.error("Invalid number of files");
                    return false;
                }
                this.hashsalt = this.makeHash(10);
                this.adminhash = this.makeHash(10);
                var sql = this.db.prepare(`INSERT INTO "upload" (hashsalt, adminhash, upload_unix) VALUES (?, ?, ?)`);
                var result = sql.run(this.hashsalt, this.adminhash, Math.floor(Date.now() / 1000));
                this.id = result.lastInsertRowid;
                this.hashid = this.id2hashid(result.lastInsertRowid);
                this.dir = this.hashid + this.hashsalt;
                var fs = require('fs');

                if (!fs.existsSync("uploads/" + this.dir)) {
                    fs.mkdirSync("uploads/" + this.dir);
                }

                this.loaded = true;
                return true;
            }
        }

        load(hash) {
            if (!this.loaded) {
                var shash = this.splitHash(hash);
                this.hashid = shash[0];
                this.id = this.hashid2id(this.hashid)
                this.hashsalt = shash[1];
                this.dir = this.hashid + this.hashsalt;

                var sql = this.db.prepare(`SELECT count(id) AS "count" FROM "file" WHERE upload_id=?`);
                var num_files = sql.get(this.id)["count"];
                if (typeof num_files == "number" && num_files > 0) {
                    this.num_files = num_files;
                } else {
                    console.error("Invalid number of files");
                    return false;
                }

                var sql = this.db.prepare(`SELECT EXISTS(SELECT 1 FROM "upload" WHERE id=? AND hashsalt=? LIMIT 1) AS "exists"`);
                var result = sql.get(this.id, this.hashsalt);



                if (result["exists"]) {
                    console.log("LOADED: ", result);
                    this.loaded = true;
                    return true;
                } else {
                    console.log("Not Found");
                    return false;
                }
            }
        }

        getNumFiles() {
            return this.num_files;
        }

        isLoaded() {
            return this.loaded;
        }

        getDir() {
            return this.dir;
        }

        loadFiles() {
            this.files = this.db.prepare(`SELECT filename FROM "file" WHERE upload_id=?`).all(this.id);
            console.log(this.files);
        }

        getFiles() {
            this.loadFiles();
            return this.files;
        }

        getFileByIndex(index) {
            return this.getFiles()[index];
        }

        registerFile(filename) {
            var sql = this.db.prepare(`INSERT INTO "file" (filename, upload_id) VALUES (?, ?)`);
            var result = sql.run(filename, this.id);
            return result;
        }

        delete() {

        }

        getHash() {
            return this.hashid + this.hashsalt;
        }

        getHashId() {
            return this.hashid;
        }

        getAdminHash() {
            return this.adminhash;
        }


        id2hashid(id) {
            var hashid = "";
            id = id.toString();
            for (var i = 0; i < id.length; i++) {
                hashid += this.absrc[id.charAt(i)];
            }
            return hashid;
        }

        hashid2id(hashid) {
            var id = "";
            for (var i = 0; i < hashid.length; i++) {
                var index = this.absrc.findIndex((letter) => letter == hashid.charAt(i));
                if (!(index < 0)) {
                    id = id + index.toString();
                };
            }
            return parseInt(id);
        }

        // https://stackoverflow.com/questions/1349404/generate-random-string-characters-in-javascript
        makeHash(len = 10) {
            let result = '';
            const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
            const charactersLength = characters.length;
            let counter = 0;
            while (counter < len) {
                result += characters.charAt(Math.floor(Math.random() * charactersLength));
                counter += 1;
            }
            return result;
        }

        splitHash(hash) {
            return [hash.slice(0, hash.length - 10), hash.slice(hash.length - 10, hash.length)]
        }

    }
}